Apparatus for drilling oriented drain holes



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APPARATUS FOR DRILLING ORIENTED DRAIN HOLES Filed Dec. 10, 1948 3 Sheets-Shegt l /INVENTOR.

JMMA. 21mm WMJM March 16, 1954 J. A. ZUBLIN APPARATUS FOR DRILLING ORIENTED DRAIN HOLES 3 Sheets-Sheei? Filed Dec. 10, 1948 w w w w w, a J |lJ g *4 M. W I m W r1 TIL. W A M J \llflu V I I a x w M W x M M A 4 w w 4 March 16, 1954 J, A. ZUBLIN APPARATUS FOR DRILLING ORIENTED DRAIN HOLES Filed Dec. 10. 1948 3 Sheefs-Sheet 3 42 uvmvrm BY elafiaAZullzh ATTORNEYS bearing race 2| which is screw-threaded at 22 to the upper end of the hollow spindle 5.

The normally curved, flexible, resilient deflector pipe i6 is illustrated as being of the type shown in Figure 3 of my prior U. S. Patent No. 2,515,365. This deflector pipe consists of a tubular metal pipe having a slot through its walls extending in a generally helical path along and around the pipe. However, the slot deviates from a true helical path to provide along its sides intermeshing and interlocking teeth of dovetail configuration. The surfaces of the intermeshing and interlocking teeth are separated by the normal width of the slot while the pipe is in its normal unstressed configuration and the pipe is flexible within the limit of deformation permitted by the width of the slot. The faces of the teeth engage when the pipe is deformed a predetermined extent in any direction and thus limit the amount of deformation. The generally helically extending slot is designated by the reference numeral 23 and the loosely intermeshing and interlocking teeth are designated by the reference numeral 24. The deflector pipe i6 has a normal configuration which is curved. In its normal unstressed condition, the deflector pipe has a curvature approximately equal to the curvature at which the drain hole to be drilled is to deviate from the existing vertical well bore. The approximate path of such a drain hole is illustrated in Figure 1 and is designated by the reference numeral 25.

At its upper end the deflector pipe i6 is provided with a bearing race 25. The hollow spindle 2'! of a coupling member 28 is mounted for rotational as well as limited longitudinal movement within the bearing race 25. Ball bearings 25 assume both radial and thrust loads during normal drilling of a drain hole and roller bearings 30 are arranged to assume a part of the radial load.

The coupling member 28 is threadedly connected at 3| to the lower collar 32 of a flexible drill pipe 33. This flexible drill pipe 33 embodies the essential features of the flexible drill pipe illustrated and described in my prior U. S. Patent 2,515,366. The flexible drill pipe comprises a pipe having generally circumferential slots through its walls at longitudinally spaced zones along its length. The slots divide the pipe into sections. The slots are not truly circumferential in that they deviate from a true circumference to define the edges of loosely inter-engaging and intermeshing teeth of dovetail configuration. The dimensions and configuration of the teeth are such as to prevent separation of the sections by relative movement in any direction. The flexible drill pipe shown in my above mentioned Patent 2,515,366 is formed by cutting the slots through the walls of an initially unitary pipe. The flexible drill pipe shown in the present application consists of a plurality of relatively thick-walled sections 34 of hardened steel joined by relatively thin-walled sections 35. The relatively thick-walled sections 34 have the slots 35 cut therein to form the loosely intermeshing and inter-engaging teeth 31. The sections 34 and 3-5 are joined by welded seams 38 as best illustrated in Figures 4 and 5. This arrangement facilitates manufacture of the flexible drill pipe and reduces the weight for a drill pipe of a given length and sturdiness.

The uppermost slotted section of the flexible drill pipe 33 is designated by the reference numeral 39 and .a threaded connector member 40 is secured thereto by means of welding material 4|. The connector member 4|! is threadedly connected at 42 to a collar 43 which is in turn threadedly connected to a rigid drill pipe 44 which extends to the top of the well.

Referring again to the lower end of the apparatus as illustrated in Figure 8, it will be seen that a flexible drive member e5 has its lower end threadedly connected at 46 to the upper end of the tubular stem l5. The drive member 45 is a flexible tubular member similar to that described in my above mentioned Patent 2,515,366 and to the flexible drill pipe 33 described above.

' It consists of a plurality of tubular sections or links in end-to-end relationship which are loosely and flexibly connected together by means of inter-engaging and interlocking teeth of dovetail configuration. Figure 8 illustrates one of the tubular sections or links 41 connected to a similar section 48 by means of teeth of dovetail configuration formed by the slot 49 which is similar to the slots 35 in the flexible drill pipe 33. Roller bearings 56 may be provided to reduce friction between the interior surface of the deflector pipe l6 and the exterior surface of the drive member 45 when that drive member is rotating relative to the deflector pipe. The character of the drive member 55 is such that it can rotate within the deflector pipe 16 while that deflector pipe is in its normally curved condition. The flexibility of the drive member 45 results from the loosely inter-engaging and interlocking teeth between adjacent sections and no deformation of the metal of the sections is necessary.

The width of the slot 49 between sections of the drive member 55 permits considerable alteration in the overall length of the drive member. The drive member 55 will be considerably longer when it is subjected to tension than when it is exposed to compressive stresses. This characteristic of the drive member 45 is important to the functioning of the clutch assembly hereinafter described by which rotation of the deflector pipe l6 Within the well bore is effected to secure proper orientation of the apparatus to drill a drain hole in the desired azimuth.

The bearing race 26 at the upper end of the deflector pipe I6 is provided at its lower edge with a single large tooth 5| of generally semi-circular configuration. The tooth 5| always remains stationary with respect to the upper end of the deflector pipe. The uppermost section 52 of the drive member 55 carries at its upper edge a tooth 53 which is complementary in form to the tooth 5|. This uppermost section 52 of the drive member 45 is threadedly connected at 54 to the lower end of the hollow stem 21 of the coupling member 28. The tooth 53 is therefore stationary relative to the coupling member 28. It has been pointed out above that the coupling member 28 is free to move longitudinally within the bearing race 26 at the upper end of the deflector pipe Hi. It will be apparent from this description that upward movement of the hollow stem 21 and the uppermost section 52 of the drive.

member 45 relative to the upper end of the deflector pipe IE will cause the teeth 5! and 53- to engage in the manner illustrated in Figure '3. Downward movement of the stem 2! and section 52 relative to the upper end of the deflector pipe.

is will cause the teeth 5| and 53 to disengage and to occupy the positions illustrated in Figure 6. The engagement and disengagement of the teeth 5| and 53 is accomplished by raising and lowering the drill pipe 44 which extends to the top of thewell. The ability of the drive member 45 to assume different lengths permits engagement and disengagement of the teeth i and 53 in spite of the fact that the drive member is secured to the deflector pipe it at the lower end thereof.

A central longitudinal. passageway extends through all portions of the apparatus for conducting drilling mud through the apparatus to the drilling bit it. The flexible drill pipe 3'5 is provided with a longitudinally extending flexible hose 55 of reinforced rubber or other suitable material. The upper end of the hose 55 is secured by means of rivets 5.5 to a coupling member 51 which in turn is screw-threaded to the lower .end of the connector member fill. The lower end of the hose 55 is secured by means of rivets 58 to the upper portion of the coupling 32. The hose 55 prevents loss of drilling mud through the slots 35 in the walls of the flexible drill pipe 33. A similar flexible hose extends through the interior of the flexible drive member 45. The upper end of the hose 59 is secured by means of rivets so to the uppermost section 52 of the drive member. The lower end of the hose 59 is secured by means of rivets i i to the lowermost section oz of the drive member 55. The hose 59 prevents loss of drilling mud through the slots in the walls of the drive member t5 and of the deflector pipe it.

In the operation of the device the deflector pipe is is forcibly straightened sufficiently to enable the entire apparatus to be lowered into an existing Vertical well bore tit. Energy is thus stored in the resilient deflector pipe it and the drilling bit to will exert lateral pressure on the wall of the well bore as indicated by the arrow P in Figure 2. The apparatus is illustrated in Figure l as having advanced in the initiation of the drilling of the curved bore to the point A.

By reference to Figure 3 it will be seen that when the apparatus is in the position there shown the drilling bit It, when rotated without rotation of the deflector pipe, will drill a bore which deviates laterally from the well bore 53 in the plane w-zc. This rotation of the drilling bit Ill can be accomplished merely by rotating the drill pipe t l at the surface of the well while the clutch is disengaged. However it will usually be found that when the apparatus is lowered into the well it will not be properly oriented to drill a drain hole in the desired azimuth. For example the apparatus may be oriented to drill a drain hole deviating from the Well bore in the plane a::c but it may be desired to drill the drain hole in the plane y-y. It will be apparent that the operator must ascertain the existing orientation of the apparatus and must then compute the extent of rotation of the deflector pipe it which will be required to orient the apparatus for drilling a drain hole in the desired azimuth.

Several types of orientation determining apparatus are available which can be lowered into the well. Any of these various types of orientation determining devices are suitable and it will be assumed that such a device is used to determine the direction of the line f-f which extends through fixed points on the lower portion of the deflector pipe 16. Let it be assumed that the line ff extends in the direction indicated in Figure 3 when the apparatus is positioned as there indicated. The angle b between the line ,ff and the plane x-x remains constant in the apparatus and the value of this angle is known to the operator before the apparatus is inserted in the well. Upon removal of the orientation determining device from the well the operator can compute that the plane x100 lies at an angle a (assumed to be in Figure 3) from the plane li -11 in which it is desired to drill the the drain hole. From this information it will be apparent to the operator that the deflector pipe must be rotated in one direction through an angle of 425 or in the opposite direction through an angle of 315 to secure the desired orientation. This ro= tation of the deflector pipe it can he 38.00111:- nlished by raising the drill pipe .44 at the S113? face of the well a distance .sufiicient to cause en.- gagement of the teeth 5! and 53 v.of the clutch. The drill pipe can then be rotated .at the surface of the well in a direction and to an extent sums cient to orient the apparatus for drilling a drain hole in the desired azimuth.

The flexible drill pipe 3,3 is capable of assum, ing difieren-t lengths because of the nature of the loosely interengaging and interlocking teeth which join the sections thereof. The nature of these teeth also permit limited relative rotation between sections of the pipe. tension is applied to the flexible drill pipe, as is done to cause the clutch to engage, the flex ible drill pipe assumes a definite and ffiXd maximum length and the possibility of relative rotation of the sections is eliminated. This is due to the fact that the tension on the flexible drill pipe causes the surfaces .of the teeth to engage in definite and fixed relative positions. This characteristic of the flexible drill pipe 3,3 makes it important that tension be applied in an amount suiiicient to engage the clutch and to assure that the sections of the flexible drill pipe have assumed their fixed relative positions before the orientation determinations and computations are made. It is not essential, but :I consider it adivisable to combine the tension in the drill pipe with a limited amount of rotation to make certain that all of the inter-engaging teeth between sections of the flexible drill pipe 33 are tightly pressed against each other and to make certain that the deflector pipe it is in a well defined oriented position relative to the conventional rigid drill pipe 44 above the flexible drill pipe 33. When the orientation determinations and computations have been made the orientation of the apparatus to drill in the desired azimuth may be done by rotating the entire apparatus including the deflector pipe while the clutch is engaged. If the tension applied to the drill pipe has been accompanied by limited rotation in a clockwise direction before the orientation determinations have been made, the orienting movement of the apparatus should also be in a clockwise direction.

As soon as the apparatus has been properly oriented the tension may be released from the drill pipe and the drill pipe lowered at the surface of the well to disengage the clutch and to apply drilling pressure to the bit l0 while the deflector tube it remains stationary. When the clutch is disengaged, the deflector pipe i6 is held against rotation by frictional engagement with the wall of the vertical bore and, due to its resiliency, forces the bit is into engagement with the wall of the bore at the oriented position. The

=1 bit II), of course, rotates about the center of the lower end of the tube It as its axis and thus penetrates into the formation at the preselected point. It follows that when the clutch is disengaged and the drill pipe is rotated from the surface of the well the bit ill will drill a drain hole in the However, when 7 desired azimuth. This drain hole will deviate from the existing well bore 63 in the manner indicated by the reference numeral 25 in Figure l. The curvature of the drain hole will be approximately equal to the curvature of the deflector pipe 16 when that deflector pipe is in its normal unstressed condition.

The deflector pipe 16 is never required to rotate in a curved bore and rotation of this deflector pipe in a straight bore is limited to the slight rotation which is required for orientation of the apparatus. There is thus little likelihood of fatigue failure of the metal of the deflector pipe IS. The conical rolls H and i2 on the bit l facilitate rotation of the deflector pipe for purposes of orientation when the clutch is engaged.

The lengths of the different portions of the apparatus as illustrated in Figure 1 are not necessarily representative of the relative lengths which are used in actual practice. The length of the deflector pipe 16 is preferably as short as possible consistent with obtaining the desired lateral deviation from the well bore 63. The combined lengths of the deflector pipe l9 and the flexible drill pipe 33 is preferably approximately equal to the depth or length of the deepest drain hole which is to be drilled.

My apparatus permits the drilling of laterally extending drain holes by the use of conventional drilling procedures. No special equipment is required at the surface of the well and it is possible to use any of the commercially available types of swivels and rotary tables. The teeth and 53 of the clutch will remain disengaged at all times during drilling because of the application of weight to the drill bit by the drill pipe extending to the top of the well.

The foregoing detailed description of an exemplary form of the invention has been given to enable others to understand the invention and to obtain the benefits thereof. It is to be understood that the invention is not limited to the exemplified form and that various modifications may be resorted to without departing from the scope of the invention as defined by the following claim.

Having thus described my invention, I claim:

Apparatus for drilling a curved bore deflecting from an existing well bore, said apparatus comprising a normally curved, flexible, resilient deflector tube, a flexible drive member rotatable within said deflector tube, means connecting said deflector tube and said drive member permitting limited axial movement of said deflector tube and said drive member relative to each other, a drilling bit connected to the lower end of said drive member to rotate therewith, means for securing a drill pipe to the upper end of said drive member, and clutch means including a first clutch member carried by said drive member and a second clutch member carried by said deflector tube, said clutch members being engaged by elevation of said drill pipe and being operable, when engaged, to cause said deflector tube to rotate With said drive member to permit angular orientation of said deflector tube.

JOHN A. ZUBLIN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,118,650 Lee May 24, 1938 2,296,161 Hall, Jr Sept. 15, 1942 2,336,338 Zublin Dec. 7, 1943 2,344,277 Zublin Mar. 1%, 1944 2,382,933 Zublin Aug. 14, 1945 

